DESCRIPTION: (verbatim from application) The long-term objective of the presently proposed project is to reduce the incidence of injuries to older adults that result from slip-related falls. We will induce controlled slips in young and older adults using a specially designed slipping platform. The purpose of the presently proposed project is to determine the biomechanical variables limit the ability of young and older adults to prevent a backward fall as a result of a forward-directed slip of the foot during locomotion. In particular, we will focus our attention on the non-slipping rear leg as a crucial component of recovering one's balance and avoiding a fall. We hypothesize that avoidance of a fall subsequent to a slip is dictated by the biomechanics of the non-slipping leg and that the higher rate of falling by older adults can be attributed to the biomechanics of the non-slipping rear leg. If the hypotheses are supported then the results will provide support for further investigating appropriate means by which older adults can be better protected from slip-related falls and injuries. We will test these hypotheses by addressing the following Specific Aims. Specific Aim 1: characterize the slip conditions that distinguish the ability of young and older adults to avoid a fall after slipping. Specific Aim 2: characterize the biomechanical differences that distinguish the ability of young and older adults to avoid a fall after slipping. Specific Aim 3: define the importance of the non-slipping, rear leg to avoiding a fall after slipping. The impact of the proposed work is that it will quantify biomechanical determinants of the outcome (recovery or fall) of a slipping event. The health-relatedness of the project is that it will contribute to further systematic design and testing of intervention methods that may effectively reduce the number of slip-related injuries and deaths, particularly in older adults.